RPM vs. Speed on older Nautiques

[pdxCC]

I was wondering how the RPM's equate to the speed of the boat on the mid-90's SNCB's. I believe that I still have the original prop and I heard that the RPM's /100 are close to the speed. (i.e. 3000rpm = 30mph)

I know this is a vague question and it varies boat to boat and by prop condition, but I need to reset my airguides and have no other reference.

Any help is appreciated.

Thx
Brett

[Quinner]

That will work to get you close however if you can use a hand held GPS and set at Slalom speed that is your best bet. If you also do some Slow speed skiing/riding see how close you are there after dialing in at slalom speed, if it is way off you could calibrate one speedo for Slalom and the other for 20mph or there abouts.

[93nautique0710]

my 93 is pretty dead on i let my friend use my boat last year and he didnt no anything about a nautique and he said u know your rpms are the same as your speed and i have prefect pass stargazer 30mph 3000 rpms and i love my wake edition perfect pass best 1200 dollars ever spent

[pdxCC]

Thanks for the info. I am in the process of getting an older perfectpass fitted up but I am a few months away from getting the paddle wheel cut in. I wanted to have a gauge in the interim and then to check my PP once its installed.

Cheers!

[Chexi]

I second the portable GPS method. If you don't own one, borrow one. I use a Garmin to check/reset my speedos every year. That said, since dialing it in when I first got my 99 Air 2.5 years ago, the speedos/air guides have stayed dead on since.

[Northof49]

I drive all the time with a handheld GPS. It sits in the cup holder of my 95 SN where I can check it on a regular basis. We run in a lake with a lot of weeds so the GPS helps when we loose a speedo. I am a fan of Garmins and recommend at Map76 or higher. I want Stargazer, however the garmin will have to do for now!

[DanielC]

I would also suggest you get a handheld GPS, to check speed, but that is not the biggest reason you want one. More on that a little later.

GPS is good for checking the speed, but it does not tell you how fast you ARE going, it tells you how fast you WERE going. Assuming it has maintained a good fix on several satellites. If you are driving at a steady speed, you can use it to adjust the Airguide speedos, and then the Airguides will read accurate, until they get clogged. Keep in mind GPS is speed over land, not speed through the water. Good for slalom, not so much for just about every other water skiing discipline.

pdxCC, the real reason you want a handheld GPS unit it it shows you where you are, or have been. Once you know an area of water is safe and deep enough, sticking to your old GPS tracks will put you back into the same safe water. This is important on both the Willamette and Columbia rivers around Portland. Be advised, that the Columbia does change from year to year, and sandbars on the Columbia can change, and move.